[CI] Speed up Tempest jobs

Manila CI jobs fail very often exceeding timeout.
So, do several changes to speed up Tempest jobs:

1) Separate NFS and CIFS tests between jobs.
Run NFS jobs on MySQL ones and CIFS on PostgreSQL.

2) Refactor couple of tests removing creation of redundant shares
testing the same things.

3) Increase amount of threads, to minimize probability of
running heavy test suites in one thread.

Change-Id: I6b60db039a96b47386f8ff538d1cb74559691ccc
1 file changed
tree: 7459caaf82e205bdff3539b0b81d292eb29c0507
  1. manila_tempest_tests/